Merge pull request #83 from talko/processimage

Fixes a bug that causes image retrieval to never complete if it depends on an source image URL whose request is already in flight.

Author: mallorypaine

FastImageCache/FICImageCache.m

@@ -250,7 +250,7 @@ - (void)_imageDidLoad:(UIImage *)image forURL:(NSURL *)URL {
             NSString *formatName = [entityDictionary objectForKey:FICImageCacheFormatKey];
             NSDictionary *completionBlocksDictionary = [entityDictionary objectForKey:FICImageCacheCompletionBlocksKey];
             if (image != nil){
-                [self _processImage:image forEntity:entity withFormatName:formatName completionBlocksDictionary:completionBlocksDictionary];
+                [self _processImage:image forEntity:entity completionBlocksDictionary:completionBlocksDictionary];
             } else {
                 NSArray *completionBlocks = [completionBlocksDictionary objectForKey:formatName];
                 if (completionBlocks != nil) {
@@ -314,41 +314,18 @@ - (void)setImage:(UIImage *)image forEntity:(id <FICEntity>)entity withFormatNam
         if (imageTable) {
             [imageTable deleteEntryForEntityUUID:entityUUID];
 
-            [self _processImage:image forEntity:entity withFormatName:formatName completionBlocksDictionary:completionBlocksDictionary];
+            [self _processImage:image forEntity:entity completionBlocksDictionary:completionBlocksDictionary];
         } else {
             [self _logMessage:[NSString stringWithFormat:@"*** FIC Error: %s Couldn't find image table with format name %@", __PRETTY_FUNCTION__, formatName]];
         }
     }
 }
 
-- (void)_processImage:(UIImage *)image forEntity:(id <FICEntity>)entity withFormatName:(NSString *)formatName completionBlocksDictionary:(NSDictionary *)completionBlocksDictionary {
-    FICImageFormat *imageFormat = [_formats objectForKey:formatName];
-    NSString *formatFamily = [imageFormat family];
-    NSString *entityUUID = [entity UUID];
-    NSString *sourceImageUUID = [entity sourceImageUUID];
-    
-    if (formatFamily != nil) {
-        BOOL shouldProcessAllFormatsInFamily = YES;
-        if (_delegateImplementsShouldProcessAllFormatsInFamilyForEntity) {
-            shouldProcessAllFormatsInFamily = [_delegate imageCache:self shouldProcessAllFormatsInFamily:formatFamily forEntity:entity];
-        }
-        // All of the formats in a given family use the same source asset, so once we have that source asset, we can generate all of the family's formats.
-        for (FICImageTable *table in [_imageTables allValues]) {
-            FICImageFormat *imageFormat = [table imageFormat];
-            NSString *tableFormatFamily = [imageFormat family];
-            if ([formatFamily isEqualToString:tableFormatFamily]) {
-                NSArray *completionBlocks = [completionBlocksDictionary objectForKey:[imageFormat name]];
-                
-                BOOL imageExistsForEntity = [table entryExistsForEntityUUID:entityUUID sourceImageUUID:sourceImageUUID];
-                BOOL shouldProcessFamilyFormat = shouldProcessAllFormatsInFamily && imageExistsForEntity == NO;
-                if (shouldProcessFamilyFormat || [completionBlocks count] > 0) {
-                    [self _processImage:image forEntity:entity imageTable:table completionBlocks:completionBlocks];
-                }
-            }
-        }
-    } else {
-        FICImageTable *imageTable = [_imageTables objectForKey:formatName];
-        NSArray *completionBlocks = [completionBlocksDictionary objectForKey:formatName];
+- (void)_processImage:(UIImage *)image forEntity:(id <FICEntity>)entity completionBlocksDictionary:(NSDictionary *)completionBlocksDictionary {
+    for (NSString *formatToProcess in [self formatsToProcessForCompletionBlocks:completionBlocksDictionary
+                                                                         entity:entity]) {
+        FICImageTable *imageTable = [_imageTables objectForKey:formatToProcess];
+        NSArray *completionBlocks = [completionBlocksDictionary objectForKey:formatToProcess];
         [self _processImage:image forEntity:entity imageTable:imageTable completionBlocks:completionBlocks];
     }
 }
@@ -388,6 +365,58 @@ - (void)_processImage:(UIImage *)image forEntity:(id <FICEntity>)entity imageTab
     }
 }
 
+- (NSSet *)formatsToProcessForCompletionBlocks:(NSDictionary *)completionBlocksDictionary entity:(id <FICEntity>)entity {
+    // At the very least, we must process all formats with pending completion blocks
+    NSMutableSet *formatsToProcess = [NSMutableSet setWithArray:completionBlocksDictionary.allKeys];
+
+    // Get the list of format families included by the formats we have to process
+    NSMutableSet *families;
+    for (NSString *formatToProcess in formatsToProcess) {
+        FICImageTable *imageTable = _imageTables[formatToProcess];
+        FICImageFormat *imageFormat = imageTable.imageFormat;
+        NSString *tableFormatFamily = imageFormat.family;
+        if (tableFormatFamily) {
+            if (!families) {
+                families = [NSMutableSet set];
+            }
+            [families addObject:tableFormatFamily];
+        }
+    }
+
+    // The delegate can override the list of families to process
+    if (_delegateImplementsShouldProcessAllFormatsInFamilyForEntity) {
+        [families minusSet:[families objectsPassingTest:^BOOL(NSString *familyName, BOOL *stop) {
+            return ![_delegate imageCache:self shouldProcessAllFormatsInFamily:familyName forEntity:entity];
+        }]];
+    }
+
+    // Ensure that all formats from all of those families are included in the list
+    if (families.count) {
+        for (FICImageTable *table in _imageTables.allValues) {
+            FICImageFormat *imageFormat = table.imageFormat;
+            NSString *imageFormatName = imageFormat.name;
+            // If we're already processing this format, keep looking
+            if ([formatsToProcess containsObject:imageFormatName]) {
+                continue;
+            }
+
+            // If this format isn't included in any referenced family, keep looking
+            if (![families containsObject:imageFormat.family]) {
+                continue;
+            }
+
+            // If the image already exists, keep going
+            if ([table entryExistsForEntityUUID:entity.UUID sourceImageUUID:entity.sourceImageUUID]) {
+                continue;
+            }
+
+            [formatsToProcess addObject:imageFormatName];
+        }
+    }
+
+    return formatsToProcess;
+}
+
 #pragma mark - Checking for Image Existence
 
 - (BOOL)imageExistsForEntity:(id <FICEntity>)entity withFormatName:(NSString *)formatName {